Studies of the natural history of insect sting allergy

The natural history of insect sting allergy was studied by observations of the results of re-sting on two groups of individuals who had prior sting anaphylaxis, had demonstrable venom-specific IgE, and did not receive venom immunotherapy. In the first study group, the mean duration between the initial sting reaction and re-sting exposure was 4.5 years; the re-sting reaction rate was 35%/sting and 50%/patient. In the second long-term study, the mean duration between the sting reaction and re-sting was 7.3 years; the re-sting reaction rate was 12%/sting and 12%/patient. Factors influencing the likelihood of re-sting reaction included older age, and the occurrence of cardiovascular/respiratory anaphylactic symptoms. In a prospective and retrospective study of 133 patients with large local reactions, re-sting observations indicated an extremely high recurrence of similar large local reactions, with little risk of subsequent anaphylaxis. These data suggest that: (1) insect sting anaphylaxis is a self-limiting process for the majority of individuals, and (2) re-stings in individuals who have had large local reactions have a relatively benign prognosis.